Papermaking machine



Jan. 24, 1967 Filed Aug. 21, 1964 D. H. KUTCHERA ETAL PAPERMAK I NGMACHINE FIG D. H. KUTCHERA ETAL 3,299,531

I Jan.24, 1967' PAPERMAKING MACHINE 4 Sheets$heet 3 Filed Aug. 21} 1964FIG.5.

Jan. 24, 1967 i KUTCHERA L 3,299,531

PAPERMAKING MACHINE Filed Aug. 21, 1964 4 Sheets-Sheet 4 United StatesPatent 3,299,531 PAPERMAKING MACHINE Don H. Kutcliera, Oshkosh, andRobert M. Eiss, Neeuah, Wis., assignors to Kimberly-Clark Corporation,Neenali, Wis., a corporation of Delaware Filed Aug. 21, 1964, Ser. No.391,210 3 Claims. (Cl. 34-125) The invention relates to papermakingmachines and, more particularly, to steam heated driers for the paperweb made on such machines. Such driers generally include an outer,relatively thin shell mounted on and sealed with respect to a pair ofdrier heads which, in turn, are fixed to end journals for rotatablysupporting the drier in suitable bearings.

It has previously been proposed to provide steam heated driers,particularly for papermaking machines, which have shells formed withinternal ribs and grooves, such a con struction being shown, forexample, in British Patent 939,926, issued to Beloit Iron Works andpublished on October 16, 1963.. The ribs and grooves terminate anappreciable distance (which may be at least 6 to 8 inches) away from theends of the shell, with relatively long grooves between the last rib oneach end of the shell and the adjacent end of the shell. It has alsobeen proposed to provide such a construction as illustrated in thispatent with each of the relatively long grooves being replaced by aninwardly tapering truncated conical surface on each end extending fromthe largest diameter of the grooves substantially to the smallerinternal diameter of the ribs at the ends of the shell. The end ribs aresubstantially in line with the edges of the paper web dried on the drum,and the inwardly truncated surfaces within the drier shell decrease theheat conductivity through the shell adjacent the edges of the sheet toreduce the drying effect on the sheet edges.

It has, however, been found that this construction gives rise to a highlocalized stress at the very edge of the first internal rib on each endof the shell, and there is also a localized stress (which is not quiteas high, however, as that just mentioned) existing in the groove betweenthe two end ribs on each end of the shell. Due to the high localizedstresses at these places, the shell is weaker at these places. Also, theshell, due to these stresses, when under steam pressure, becomesrelatively too small in the vicinity of the first rib; so that apressure roll in contact with the drier, which holds a felt carrying thepaper web in contact with 'the drier, does not mate properly with thedrier. Also, under these conditions, a doctor blade for doctoring offthe paper web from the shell does not fit properly with the shell. Inaddition, it has been found that neither the long internal grooves onthe ends of the shell nor the inwardly tapering truncated conicalsurfaces provide the exact temperature on the external surface of thedrier drum which should exist for neither drying the web edges to toogreat an extent nor leaving the web edges relatively damp.

It is an object of the invention to provide an improved, internallyribbed, drier shell of such construction that the high local stressesabove mentioned do not exist, whereby the drier shell does not haveunduly small diameters in the vicinity of the first ribs and in thevicinity of the sheet edges. It is also an object of the invention toprovide an improved drier of this type in which the ribs and groovesextend practically to the ends of the shell and in which the ribs andgrooves are of such construction that a proper heat transfer is attainedin the vicinity of the web edges so that neither undue drying of sheetedges nor wet sheet edges result.

In its preferred form, the invention contemplates an internally ribbeddrier shell having ribs which decrease in height at the very ends of thedrier shell. The localice ized stress conditions as mentioned above arethus overcome, and the transmission of heat through the drier shelladjacent its ends is also properly reduced.

The invention consists of the novel constructions, arrangements anddevices to be hereinafter described and claimed for carrying out theabove-stated objects, and such other objects, as will be apparent fromthe following description of a preferred form of the invention,illustrated with reference to the accompanying drawings, wherein:

FIG. 1 is a vertical sectional view of a drier drum having therein aplurality of condensate pickup headers, including a particular header57a, extending axially within the drum and located adjacent to the innersurface of the shell of the drum;

FIG. 2 is a fragmentary vertical sectional view of the drum taken on anenlarged scale;

FIG. 3 is a view similar to FIG. 2 but on a still further enlarged scaleand with certain parts being deleted for the purpose of betterillustration;

FIG. 4 is a view similar to FIG. 3 showing a prior art construction;

FIG. 5 is a fragmentary side elevational view of a papermaking machineincorporating the drier drum of the invention;

FIG. 6 is a sectional view taken on plane 66 of FIG. 1; and

FIG. 7 is a fragmentary sectional view showing the particular condensatepickup header 57a and adjacent parts, and also taken on plane 66 of FIG.1.

Like characteristics of reference designate like parts in the severalviews.

Referring now to the drawings, the drier drum illustrated in FIG. 1comprises a thin cylindrical outer shell 10 which is rigidly secured atits ends to relatively flat ring-shaped heads 11, each of which issupported by a hollow central shaft 12. The shell is provided at eachend with an integral bolting flange 13 which is machined to mate with asimilar peripheral flange 14 of the adjacent drier head 11. The rigidattachment of the shell to the head may be made by means of a pluralityof bolts 15 inserted from the inside of the shell and drawn up by meansof nuts on the outside of the head. Each of the heads 11 is providedwith a manhole 16 to provide access to the interior of the drier forassembly and maintenance.

A cylindrical section 17 is formed integrally with each of the heads andextends inwardly therefrom. Each of the cylindrical sections 17 isprovided at its inner end with a bolting flange 18. A plurality of heavystaying members 19 extend between the heads longitudinally of the drierand connect the oppositely facing bolting flanges 18.

The central shaft 12 is formed in two halves 20 and 21 which are boltedtogether at the longitudinal center of the drier. Near each end theshaft 12 is provided with an enlarged bolting flange 22 to which theheads 11 are rigidly secured by means of a plurality of bolts. The shaft12 is extended at each end to provide journals 23 for rotatablysupporting the drier, and a shaft extension 24 is provided at one end ofthe shaft 12 for mounting adriving gear or sprocket or the like.

The central shaft 12 is hollow to provide for the introduction of aheating medium, such as steam, at one end and its removal at the other.A diaphragm 25 is provided between the shaft halves 2t) and 21 andprovides chambers 26 and 27 in the shaft 12. Steam under pressure isconnected by any suitable conduit means with the chamber 26, and thechamber 27 is connected by any suitable conduit means with a steamdischarge reservoir or the like, both conduit means extending throughthe ends of the shaft 12. Steam discharge jets 28 are provided in thediaphragm 25 and connect the chamber 26 with the chamber 29 formed bythe shell 1t and heads 11.

The drier may be mounted in a papermaking machine as illustrateddiagrammatically in FIG. .5. The journals 23 of the shaft 12 may bemounted in bearings 30 which are secured to a supporting frame 31. Thewet paper web to be dried is carried by a felt web 32 which travelsaround felt rolls 33. The paper web is forced against the surface of thedrier shell by a pressure roll 34 which is rotatably mounted in brackets35 attached to arms 36. The arms 36 are each pivoted at 37 to the frame31, and the pressure roll 34 is forced against the surface of the driershell 10 by a hydraulic motor 33 which bears against each arm 3d.

The dried paper web is removed from the surface of the drier shell by acreping doctor 'which includes a doctor blade 39 removably securedwithin a doctor blade holder 41?. The blade 39 and holder 40 may besupported by conventional mechanism including shafts 41 carried by theholder 40 and rotatably mounted Within guide blocks 42. The blocks 42,in turn, are slidably mounted within a slide assembly 43 attached to apivot frame 44 carried by the frame 31. Through the slide arrangementprovided by guide blocks 42 and slide assembly 43, the vertical positionof the doctor blade 39 can be varied as desired to obtain the bestcreping angle. The doctor blade holder 40 and the blade 39 are pivotedfrom a toggle mechanism 44 which is attached through lever arm 45 to oneof the shafts 41. In addition, a spring loading mechanism 46 isconnected through the toggle mechanism 44 to provide a resilient contactfor the doctor blade against the surface of the drier shell 10.

According to the invention, the drier shell 10 is provided on itsinternal surface to within a few inches (6 inches, for example) of theends of the internal surface with a plurality of circumferentiallycontinuous and axially spaced ribs 47 spaced by grooves 48. The ribs 47are all of the same radial height, and the grooves 48 separating theribs 47 have the same radial depth. The bottoms 48z of the grooves arepreferably round in cross section, as illustrated, and they terminate inan imaginary cylinder 49 which has a constant radius 50 from thelongitudinal center line 51 of the shell 10. The innermost surfaces ofthe ribs 47 in cross section are flat, and they terminate in animaginary cylinder 52 which is at a constant distance 53 from the centerline 51.

The inner surface of the shell 10, on its ends adjacent each flange 13,is provided with a plurality of grooves 48a, 48b, 48c, 48d, 48e, and 48which are of decreasing depth. The grooves provide ribs 47a, 47b, 47c,47d, and 4712, the innermost surfaces of which are disposed on thecylinder 52, but which decrease in height in accordance with thedecreasing depth of the grooves 48a to 48 The bottoms of the grooves 48ato 48) in cross section of the shell as illustrated .in FIG. 3 aredisposed on an are 54 described by a radius 55 which may have a lengthof 23 inches, for example, and which may well be between 20 inches and30 inches for a drier of about 140 inches in diameter. It will be notedthat all of the ribs 47 and 47a to 47a have substantially the same widthin cross section, measured axially of the shell 10.

The above-described construction illustrated in FIG.3, having the endgrooves 48a to 48 may be contrasted with the prior art shell structureillustrated in FIG. 4. The FIG. 4 drier shell structure includes atruncated conical, inwardly tapering surface 56 which is substituted forthe ribs 47a to 47e and the separating grooves 481? to 48].

During operation, steam condensate forms within the shell 10 andparticularly within the grooves 48 and 48a to 48 The condensatewithdrawal system comprises a plurality of pickup header-s 57 includinga particular header 57a; and there may be, for example, .5 or 10 ofthese distributed about the shell. The headers 57 are supported withrespect to the stay members 19 and flanges 18 by means of a plurality ofsupports 58 which are fastened to both the headers 57 and to the stays19 and flanges 18.

The headers 57 are each connected to a tube 59 that is disposed incircular form within the shell 10. The tube 59 is made up of a pluralityof arced portions, 5%, 59b, etc., and two end portions 59 and 5%, witheach of the end portions being connected to the chamber 27.

A plurality of small diameter ejector pipes 60 (see FIG. 2) extend fromthe headers 57 into the grooves 48 and 48a to 48 The ejector pipes 60from each of the headers 57 may be located in each of the grooves 48 and48a to 43 in alternate ones of the grooves or in any predeterminedpattern with respect to the grooves; and they may be set at differentheights within the grooves so as to provide the desired insulatingaction. It will be understood that the more condensate liquid thatremains in a groove the more insulating action there will be, in view ofthe fact that the condensate is an insulator.

Referring to FIG. 2, it will be observed that the individual ejectorpipes 60a, 6%, 60c, 60d and 60e, connected with the particular header 57that is illustrated, are disposed in separated grooves 48; and each ofthese ejector pipes is set at a so-called normal depth close to thebottom 48z of its groove to maintain a minimum amount of condensatewithin the groove so that the heat transfer is at a maximum. There may,instead, of course, be an ejector pipe 60 located in each of thesegrooves to assure that the condensate remains at a minimum within all ofthese grooves and to assure maximum heat transfer. Alternately, ejectorpipes may be disposed in various groups or patterns of the grooves 48.Ejector pipes 60 and dtlg are located in the grooves 480 and 48d, andboth of these ejector pipes are raised with respect to the bottoms ofthe grooves so as to maintain more than the normal amount of condensatewithin the grooves to, thus, provide some insulating effect by thecondensate, lowering the temperature on the outside surface of the shell10 opposite these grooves more than would be the case if this condensatewere not provided. The groove 482 in the arrangement shown in FIG. 2,has purposely been provided without an ejector pipe so as to allow it tofill completely with condensate for thus purposely decreasing thetemperature of the shell 10 in the vicinity of the groove 48e. If itwere desired in connection with certain widths or weights of Web W toinstead have the temperature of the shell 10 on its exterior surfacehigher in the vicinity of the groove 48a, an ejector pipe would beprovided for the groove 48a.

In operation, a web W is carried by the drier shell 10, and the drier isrotated. The web W passes from the felt 32 on to the external surface ofthe shell 10, and the web W is dried on the shell and is creped from theshell by the doctor blade 39. The edges of the web W terminateapproximately in alignment with the groove 48c as is shown in FIG. 3.The drier shell 10 of the invention may be made of many differentdiameters and lengths; however, the web W, for example, may have a widthof 169 inches; the shell 10 may have a length of 172% inches; and thecomplete face of the drier, including the heads 14, may have a length of181 /2 inches. The overall diameter of the shell 10 may, for example, be144% inches. The distance from the outer side of the groove 48 to thecenter line of the first full-sized groove 48 (the groove next to thefirst shallower groove 48a) may be 7 inches, for example.

In the prior art construction as shown in FIG. 4, the truncated conicalsurfaces 56 extended to the grooves 48a, and since there were noadditional grooves between the ends of the drier shell and the grooves48a, there were high stress areas at the bottoms of the grooves 48a.There were also high stress areas at the bottoms of the next grooves 48.These high stress areas were weaker than other parts of the shell at thebottoms of these grooves 48a and 48 and also, as a more immediate sourceof trouble, caused the shell to have too small a diameter in planespassing approximately through the grooves 48a and the adjacent grooves48. Although this decreased diameter could be measured only in thethousandths of an inch, nevertheless, since very exact dimensions arerequired for the proper operation of the pressure roll 34 in conjunctionwith the drier and for the operation of the creping doctor blade 39 inconnection with the drier, the exact nip and blade pressures that wereproper did not exist. Also, the rate of heat transfer through thetruncated conical surfaces 56 was not as required, and a web on thesesurfaces of the drier could not be given the same drying treatment as inthe middle regions of the web if it extended over the truncated surfaces56, so therefore the web W actually used was limited in width to alocation substantially in line with the rib 48.

With our improved construction illustrated in FIG. 3, a wider web W maybe uniformly dried since the sides of the ribs 47 and 47a to 47e havesteam in contact with them; and there is substantial heat transfer onthe interior surface of the drum, since the radial surfaces of the ribsand also their axially extending surfaces on the cylinder 52 aresubstantially clear of condensate due to centrifugal force. The rate ofheat transfer through the end regions of the shell is properlycontrolled due to the fact that the grooves 48a to 48 successivelydecrease in depth and the sides of the ribs 48a to 48 correspondinglydecrease in radial height. Due to the fact that there are greaterthicknesses of metal between the bottoms of the grooves 48a to 48 andthe exterior surface of the shell 10*, the rate of heat transfer is lessin these regions than would be the case if full depth grooves 48 werecontinued to the end of the shell; however, this is desirable since theshell ends 11 also provide a heating effect for the edges of the web W.It is desired that the grooves 48b, 48c, and 48d be deeper than would bethe case if they were disposed on a truncated conical surface similar tothe surface 56 in order to provide the proper heating effect for theedges of the web W, and for this reason the bottoms of the grooves 48ato 48] are disposed on the are 54 described by the radius 55.

The addition of the grooves 48b to 48 to the construction assures thatthe high stresses previously described in connection with the prior FIG.4 structure do not exist in the vicinity of each groove 48a and the nextgroove 48. The action of the grooves 48b to 48 in providing this resultmay be compared to the case in which a single saw cut is provided in onesurface of a beam, in either the lower or upper surface of the beam. Thestress in the vicinity of the single saw cut is very high when a bendingmoment is put on the beam. On the other hand, if a number of saw cutsare provided adjacent this first saw cut, the stress at the first sawcut will be materially reduced. Accordingly, with the structure shown inFIGS. 1, 2 and 3, there is stress in the shell 10' adjacent its ends andthere is a bending of the shell; however, the stress is more uniform andthe bending is more uniform due to the decreasing depth grooves 48b to48 provided adjacent the ends of the shell. Also, since the relativelysmall diameter, peripherally low places have been eliminated from theexterior surface of the shell 10 by the provision of the extra grooves48b to 48 there is a more uniform nip pressure between the pressure roll34 and the drier shell 10 and between the doctor blade 39 and the driershell; and there is a more uniform dewatering and web transferringaction by the pressure roll- 34 and a more uniform creping action by thedoctor blade 39.

The stayed drier drum construction, including the stays 19 is disclosedand claimed in the US. patent of H. E.

Malmstrom et al. 3,099,543; and as has been quite fully described inthis patent, the stays substantially reduce the stresses that exist atthe ends of the drier drum shell and in the flanges of the shell thatare attached to the flanges of the drum ends. The grooves 48a to 48 thatdecrease in depth have the advantageous effect of further reducingstress in the shell 10 adjacent to the ends of the shell; and, since thegrooves 48a. to 48 decrease in depth, they also provide additionalstrength at the ends of the drier drum.

Although the ribs 47 of the invention have been described and shown asbeing circular, a helical rib formation may instead be utilized. In thelatter case, the grooves 48 may be cut into the shell 10 as a singlethread, or the grooves may constitute multiple threads.

As is illustrated in FIG. 3, the grooves 48 are preferably of less width(axially of the shell) than are the ribs 47. The ribs 47, for example,may be /8 inch wide axially of the shell, and the grooves 48 may beslightly less than /2 inch wide. It will be understood, of course, thatthese dimensions may be varied considerably while still obtaining theadvantages of the invention.

As above described, the condensate is removed from the grooves 48 bymeans of the thin tubes 60 that extend into the grooves 48. Preferablythe tubes 60 extend very close to the bottoms of the grooves 48 in themiddle region of the shell 10 so as to assure that maximum heattransmission is obtained in this portion of the shell. It will beunderstood that the water condensate from the steam acts as insulationand retards heat transmission. The heat transmission through the ends ofthe shell 10, in particular, may be controlled by raisin-g and loweringthe condensate withdrawal tubes which are disposed in the grooves 48a to48 Therefore, more or less condensate may be allowed to remain in thesegrooves so as to increase or decrease the heat transmission through theends of the shell 10 to assure that the edge regions of the web W securethe same drying effect as do the middle regions of the web W.

The spiral threaded construction above mentioned in connection with thecondensate withdrawal tubes may be considered advantageous in view ofthe fact that if one or more of the tubes 60 clogs, the condensate willrun through the helical groove and through adjacent tubes 60 forwithdrawal of the condensate. Thus, a relatively cool peripheral bandthat might occur on the drum due to the plugging of the condensatewithdrawal tubes 60- in a single groove 48 cannot occur. It will beobserved from FIG. 2 that withdrawal tubes 60 may be hung from any ofthe stays 19 so that the withdrawal tubes may be located practically atany position within the drier shell 10. In the illustrated form of thedrier, there may, for example, be 10 to 16 stays 19 equidistantlylocated around the center of the drier shell, and steam withdrawal tubes60, if required, suspended from all of these stays.

We wish it to be understood that the'invention is not to be limited tothe specific constructions and arrangements shown and described, exceptonly insofar as the claims may be so limited, as it will be apparent tothose skilled in the art that changes may be made without departing fromthe principles of the invention.

What is claimed is:

1. A drier drum comprising an outer cylindrical shell, a head on eachend of said shell and forming a steam receiving cavity within the shell,a pair of journals on opposite ends of the drum for rotatably mountingthe drum, and means for introducing steam into said cavity, said shellon its inner surface being provided with ribs and grooves extendinggenerally circumferentially, said grooves gradually decreasing in depthat the ends of the shell for decreasing the transmission of heat throughthe shell and for reducing the local stresses at the ends of the shell.

2. A drier drum comprising an outer cylindrical shell, a head on eachend of said shell and forming a steam receiving cavity within the shell,a pair of journals on opposite ends of the drum for rotatably mountingthe drum, and means for introducing steam into said cavity, said shellon its inner surface being provided with ribs and grooves extendinggenerally circumferentially, the innermost surfaces of said ribs beingdisposed at the same distance from the longitudinal center of the drumand said grooves being of uniform depth in the central region of theshell and gradually decreasing in depth at the ends of the shell withtheir bottoms at each end of the shell being disposed on an arc, viewingthe ribs and grooves in cross section on a plane passing through thelongitudinal center of the drum, for decreasing the transmission of heatand for reducing the local stresses at the ends of the shell.

3, A drier drum comprising an outer cylindrical shell, a head on eachend of said shell and forming a steam receiving cavity Within the shell,a pair of journals on opposite ends of the drum for rotatably mountingthe drum, and means for introducing steam into said cavity, said shellon its inner surface being provided with ribs and grooves extendinggenerally circumferentially, the innermost surfaces of said ribs beingflat in cross section and being disposed on an imaginary cylinder havingits center coincident With the longitudinal center of said drum, thegrooves in the central region of said shell being uniform in depth andgradually decreasing in depth at the ends of the shell for decreasingthe transmission of heat and for reducing the local stresses at the endsof the shell.

References Cited by the Examiner UNITED STATES PATENTS 1,453,113 4/1923Hutchins .34-125 2,521,371 9/1950 Hornbostel et al. 34-125 2,893,1367/1959 Justus et al. 34-119 3,099,543 7/1963 Malmstrom et al. 34-1243,169,050 2/1965 Kroon 34-124 3,241,251 3/1966 Justus et al. 34-1243,258,851 7/1966 Vonderau 34-124 20 FREDERICK L. MATTESON, JR., PrimaryExaminer.

A. D. HERRMANN, Assistant Examiner.

1. A DRIER DRUM COMPRISING AN OUTER CYLINDRICAL SHELL, A HEAD ON EACHEND OF SAID SHELL AND FORMING A STEAM RECEIVING CAVITY WITHIN THE SHELL,A PAIR OF JOURNALS ON OPPOSITE ENDS OF THE DRUM FOR ROTATABLY MOUNTINGTHE DRUM, AND MEANS FOR INTRODUCING STEAM INTO SAID CAVITY, SAID SHELLON ITS INNER SURFACE BEING PROVIDED WITH RIBS AND GROOVES EXTENDINGGENERALLY CIRCUMFERENTIALLY, SAID GROOVES GRADUALLY DECREASING IN DEPTHAT THE ENDS OF THE SHELL FOR DECREASING THE TRANSMISSION OF HEAT THROUGHTHE SHELL AND FOR REDUCING THE LOCAL STRESSES AT THE ENDS OF THE SHELL.